Positioning in robotics has alway been a challenge. For outdoor, robots GPS issolving most of the practical problems, but indoor, precise localization isstill done using expensive proprietary systems mainly based on an array ofcameras. In this talk, I will present the loco positioning system: an open source UltraWide Band radio-based local positioning system, why we need it and how itworks. I will also speak about its usage with the Crazyflie 2.0 open sourcenano quadcopter, of course ending with an autonomous flying demo. I am Arnaud Taffanel, co-founder of Bitcraze. Bitcraze is designing and makingthe Crazyflie 2.0 nano quadcopter, a flying open source development platform.We are designing, making and selling hardware platforms and releasing allsoftware as open source projects on Github. From the beginning of the Crazyflie project, when it was still an after-workfun project, we were dreaming of a Local Positioning System that would allowsus to fly the quadcopter autonomously. For years, the only viable solutionswhere very expensive camera-based motion capture systems. We have beenassisting researchers using the Crazyflie with this kind of system but it wasout of our reach and out of reach for most of the community. About a year ago, we discovered that a company, Decawave, had released anultra-wide-band radio module that would allows us to build an LocalPositioning System for a fraction of the price of the motion captures system.This became the Loco Positioning System and it is still under heavydevelopment with the help the community. The Loco Positioning System hardwarehas been released last summer in "early access" which means that the hardwarewas finished and tested but that much of the software and algorithm were stillunder development. We now have a flying system. With the help of researchers and industrials, weare starting to have state-of-the art algorithm for position estimation andautonomous flight. Currently the main users for the LPS and Crazyflie areuniversities for research and education, technical artists for shows andindustrials for research and tech demos. In the future, technologies andalgorithm developed for the LPS will be used for even-more affordablepositioning system (for example based on webcams) to allow anyone to play withautonomous flying platforms.